In a computer system in which a plurality of storage apparatuses are connected to a host computer via a network, a scheme of logically managing a plurality of storage apparatuses as one storage resource is being adopted. Here, the computer system adopts a configuration where, for example, alternate path software is installed in the host computer, and the host computer uses the function of the alternate path hostware to logically recognize a plurality of storage systems as one storage resource (virtual storage system) (refer to PTL 1). The alternate path software manages the logical path between the host computer and the logical storage devices (LDEVs) in the virtual storage system, and executes alternate path control. Alternate path control is the control of deciding which logical path to use among a plurality of logical paths for accessing the LDEV (Logical Device Logical Unit).
Here, each storage system manages the identifier, the LUN (Logical Unit Number) and the global LDEV number of the storage system in the virtual storage system for each logical path. Thus, the host computer can access the same LDEV regardless of which logical path among the plurality of logical paths is used for accessing the virtual storage system.